‘Excuse me. Don’t think me impertinent since I’m merely possessed of a natural and not unhealthy curiosity, but are you a man or a woman?’
Well, one doesn’t, does one? However natural and not unhealthy one's curiosity might be, one would expect the reply to be something along the lines of ‘It sounds pretty impertinent to me. Mind your own business.’ And even then, only if the individual was given to an unusual degree of politeness.
So I didn’t ask; I observed.
The hair provided no clue, being collar length and pulled back into a pony tail. The hands could have been a small man’s or a large woman’s, so no help there. The thighs had more of a masculine shape and heaviness about them, but by the same token there was no evidence of beard growth. I tried to ascertain the nature of the book that he or she was reading, but I wasn’t close enough. I could see that it was an unusually heavy book, but concluded that the heaviness of a book offers no certain indication of the gender of its reader. His or her jacket precluded any evidence being gleaned from a hint or otherwise of thoracic appendages, and there was nothing else to see. Eventually I decided that the energy I sensed was masculine, and left it at that.
I spent the remainder of the trip watching the increasing density of raindrops building up on the carriage window as the train sped west.